Doc.: IEEE 802.11-02/345r0 Submission May 2002 Albert Young, Ralink TechnologySlide 1 Enabling Seamless Hand-Off Across Wireless Networks Albert Young

May 2002

Albert Young, Ralink Technology

Slide 1

doc.: IEEE 802.11-02/345r0

Submission

Enabling Seamless Hand-Off Across Wireless Networks

Albert Young

Ralink Technology, IncPhone: 408-725-8070 x 31 e-Mail: [email protected]

May 2002


Slide 2

doc.: IEEE 802.11-02/345r0

Submission

Outline

• Introduction, Market, & Applications.

• Requirements

• Wireless LAN & Wireless WAN Progress

• Key Technologies

• Summary of Analysis

May 2002


Slide 3

doc.: IEEE 802.11-02/345r0

Submission

Introduction

• Integration of WPANs (e.g. Bluetooth), WLANs (802.11a/b/g) and WWANs (e.g. cellular networks)

• Goals for inter-working:– Seamless hand-off (no user interaction)– Robust security– Roaming agreements among carriers / operators

May 2002


Slide 4

doc.: IEEE 802.11-02/345r0

Submission

Introduction 2G 2.5G 3G 4G

Spectrum 900 MHz 1800 MHz 2100 MHz 2.4/5 GHz

Radio GSM GPRS/EDGE UMTS(W-CDMA) / CDMA2000

FHSS/DSSS/OFDM

Data rate 19.2 Kbps 80 Kbps 384 Kbps – 2 Mbps 1 – 54 Mbps

Network BSCs+MSCs +GPRS IPv6 IPv4/6

Services Voice+SMS +WAP Everything Everything

Technology GSM Packet switched Packet switched Bluetooth, 802.15, 802.11WLAN

May 2002


Slide 5

doc.: IEEE 802.11-02/345r0

Submission

Market - Mobile Internet

• Includes the wireless Web

• Also includes a rich array of value-added services that the IP network itself delivers, including variable levels of data throughput, security, quality of service, and location features.

May 2002


Slide 6

doc.: IEEE 802.11-02/345r0

Submission

Market

• Public Access WLAN over 3G– Lower costs for large volume of data– Higher speed– Location with pinpoint accuracy

• Enterprise/SMB/Home WLAN– High speed data– Voice

May 2002


Slide 7

doc.: IEEE 802.11-02/345r0

Submission

Applications• 2-way VOIP, video telephony, video

teleconferencing• 1-way streaming audio/video• 2-way interactive email/Web• Non time-critical (background email/file

downloads)• They need the inter-working of Wireless

Networks to meet various levels of requirements in mobility, security, and QoS

May 2002


Slide 8

doc.: IEEE 802.11-02/345r0

Submission

Requirements on Mobility

• Persistent connectivity. Roaming without losing network sessions

• Transparent to users• Smart hand-off between WLAN & 3G• Partnership or roaming agreements between

WWAN operators and WLAN ISPs• Protocols and methods for access control,

roaming, billing and provisioning

May 2002


Slide 9

doc.: IEEE 802.11-02/345r0

Submission

Requirements on Security

• Protocols and methods for secure tunnelling, authentication, encryption, and integrity detection

• Fast re-authentication when roaming across networks

• Centralized management and control

May 2002


Slide 10

doc.: IEEE 802.11-02/345r0

Submission

Requirements on QoS

• Efficient QoS provision

• Offering the level of QoS that the user subscribed and being charged

• Supporting the mapping between IEEE 802.1p priority levels (0-7) and IP DiffServ

May 2002


Slide 11

doc.: IEEE 802.11-02/345r0

Submission

802.11 WLAN Challenges

• Inter Access Point Protocol (IAPP)

– 802.11f draft

• Robust Security Network

– 802.11i draft

• MAC enhancement for QoS

– 802.11e draft

May 2002


Slide 12

doc.: IEEE 802.11-02/345r0

Submission

WWAN - 3G• Up to 2 Mbps for packet data, voice, and video• Enable a new generation of applications -

collaborative and multimedia services • Always-on, anywhere, high-speed data

communications service from their home networks via a secure Mobile IP tunnel

• UMTS and cdma2000. Years before compatibility barriers are lifted between competing 3G solutions

May 2002


Slide 13

doc.: IEEE 802.11-02/345r0

Submission

WWAN Challenges

• Fair and priority services – Ensure that bursts of Internet traffic headed to one

subscriber do not affect others– Deliver higher quality (higher bandwidth or lower

latency) to users that pay more

• Seamless mobility– Always-on mobile IP service, set-up and tear down

tunnels– Managing mobility within a single network, as well as

among different types of networks.

May 2002


Slide 14

doc.: IEEE 802.11-02/345r0

Submission

Inter-working Status

• 3GPP started a feasibility study on WLAN-UMTS inter-working

• ETSI BRAN• GSM Association• Architecture alternatives

– Tight inter-working– Loose inter-working

• Proprietary solutions

May 2002


Slide 15

doc.: IEEE 802.11-02/345r0

Submission

Key Technologies for Enabling Seamless Hand-Off

• Mobile IP

• Fast Hand-Off

• AAA

• IPSec

• QoS

• MAC Enabler

May 2002


Slide 16

doc.: IEEE 802.11-02/345r0

Submission

Mobile IP for Inter-System mobility

• IP should be the “Unification layer” across the WLAN and WWAN media. Generic and few assumptions about access network

• Allow seamless network traversal so that mobile users could experience ubiquitous communications that are secure and spontaneous

• A mobile user can maintain connections and permanent IP address as he roams through different subnet

May 2002


Slide 17

doc.: IEEE 802.11-02/345r0

Submission

Mobile IP

• Mobile Node (MN) go through registration process with Foreign Agent (FA), AAA, and Home Agent (HA)

• HA does authentication and traffic management• FA is the point of entry for a MN to visit different

networks– MN does not need to acquire a network (IP) address on

the foreign network

May 2002


Slide 18

doc.: IEEE 802.11-02/345r0

Submission

Drafts of IETF on Fast Hand-Off

• Various drafts on specific aspects

• Low Latency Handoffs for Multiple-Interfaced MNs

• Context Transfers Between Nodes

• Mobile IPv6 handoff by Explicit Multicast

• Protocol enhancements to minimize handoff latency to support real-time traffic

May 2002


Slide 19

doc.: IEEE 802.11-02/345r0

Submission

AAA Servers

• In use within the Internet today to provide accounting, authentication and authorization services for dial-up computers

• Valuable for mobile nodes using Mobile IP when the nodes are attempting to connect to foreign domains with AAA servers

• Identify clients by using the Network Access Identifier (NAI)

May 2002


Slide 20

doc.: IEEE 802.11-02/345r0

Submission

IPSec

• Authentication, Confidentiality and Integrity • Compliant with corporate security policies – VPN• End-to-End security provides best protection to

corporate resources• Uses IKE Phase 1 & 2 - the result is a symmetric

key used for encryption and decryption of traffic• Challenge is to achieve seamless hand-off with

VPN

May 2002


Slide 21

doc.: IEEE 802.11-02/345r0

Submission

QoS

• UMTS QoS architecture– Defines QoS profiles that are negotiated

between a mobile station and a SGSN– Supports four QoS classes: Streaming,

Conversational, Interactive, Background

• WLAN 802.11e draft in progress

• No complete solutions

May 2002


Slide 22

doc.: IEEE 802.11-02/345r0

Submission

MAC Enabler

• Radio sense of the network

• Hand-Off triggering algorithms

• Better collaboration with upper layers

• Configuration/switching based on cost, speed etc.

May 2002


Slide 23

doc.: IEEE 802.11-02/345r0

Submission

Summary of Analysis• Mobile IP allows roaming across heterogeneous

networks • No common authentication schemes• How to choose an architecture - separate AAA

server or integrated with HLR?• Needs automatic selection of network connection

and switching of networks• Real-time applications such as Voice over IP

severely challenges seamless hand-off across networks

Documents

Doc.: IEEE 802.11-02/345r0 Submission May 2002 Albert Young, Ralink TechnologySlide 1 Enabling Seamless Hand-Off Across Wireless Networks Albert Young